SUPPORTING PAPERS
2. Research Methods
anaerobic and reductive conditions, especially in the bottom waters. These conditions could accelerate the anaerobic decomposition of organic material, subsequently produce toxic materials that may endanger the lives of cultured fish. The consequences of intensive farming is the additional feed from the outside of pond as result in feeding of the pond environment is insufficient. If the feeding technique is not well controlled, it may cause impaired water quality and eventually disturbs the production, and finally resulting in the decrease of fish culture in the swamp waters.
To prevent the negative effects of the use of artificial feed in an intensive fish farming system that meet nutritional requirements by solely on artificial feed, is only through the development of eco-friendly artificial feed. The artificial feed is prepared with the addition of probiotics or through a process that offer emanation of feed ingredients. The feed can produce a low feed conversion ratio, i.e high efficient feed utilization, improve and repair of power excitatory and the digestibility of fish feed. The use of probiotics in fish and shrimp farming now becomes common, for example the use of Bacillus spp as prebion. The application can improve water quality by maintain the microbial population balance, reduce the number of pathogens simultaneously, decrease the use of chemical compounds and increase the growth of fish (Wang et al., 1999 in Irianto, 2003).
Based on the above background, it is required red to investigate the important of environmental friendly probiotic feed on a tilapia fish farming of the swamp waters. In addition, the ability of the environment to support long period farming is also need to be assesed.
3 Variables were observed in this study were:
3.1. Growth Rate of Relative Weight (%)
According to Effendie (2002), the growth rate of relative weight is defined as the percentage of weight change in a specified periode of time, and stated as following equation:
Description:
H =weight relative growth rate (%) Wt =average final weight individual (g) Wo =average initial weight individual (g) 3.2 Survival rate (%)
Survival is expressed as a percentage of number of fish that lived during the culture of a specitied period. According to Effendie (2002), survival can be calculated using the following formula :
Description:
S = survival rate
No = number of live fish at the early culture Nt = number of live fish at the end of culture 3.3 Feed conversion ratio
According to Parker (2006), feed conversion ratio can be calculated using the following formula:
Description:
FCR = feed conversion ratio F = Number of total feed given (g)
D = Total weight of fish that died during culture (g) Wo = initial weight of fish population (g)
Wt = final weight of fish population (g) 3. Results and Discussion
The rate of growth of the relative weight, survival rate and feed conversion ratio of the treated tilapia fish were observed, every two week, and the results were presented as follows:
3.1. Growth Rate of Relative Weight (%)
The growth rates of tilapia relative weight in each treatment during the culture are shown in Table 1 and Figure 1. Variance analysis of the data suggested that there was a significant difference in treatment response at 95% confidence level.
Table 1. Growth rates relative weight (%) of Tilapia
Treatment Mean (%)
A (Pellets without probiotic) 3,733a
B (Pellets with 3% probiotics) 4,341b
C (Pellets with 5% probiotics) 4,398b
D (Pellets with 7% probiotics) 4,367b
Description: The average values followed by the same letter do not differ demonstrated by Duncan multiple range test on the significant level of 5%.
Figure 1. Growth Rate Relative Weight of Tilapia (%) during the culture period Figure 1 showed that an increase in growth due to the addition of probiotics in feed. The growth rate relative weight of tilapia fed commercial diets containing no probiotics (A) was lower than that of fish fed with the addition of a commercial probiotic (B, C and D). Based on the analysis and Duncan test range of variations in the type of feed used, the rate of growth of the relative weight of tilapia, it was known that there were differences among the treatments, where treatment B was commercial diets with the addition of probiotics as much as 3% by weight relative growth rate is 4.341% treatment which was more efficient than the other treatments.
The result also showed that tilapia maintained by feeding with probiotics, used better in energy sources feed. Commercial feed had been given was already met the minimal needs of tilapia, i.e the protein between 31.97 to 34.19%, fat 3.53 to 3.91% and crude fiber between 5.04 to 7.61%.
3.2. Survival Rate
Tilapia survival rate at the end of the study in all treatments and replicates were in between of 97.78% to 98.89% (Table 2).
A=0% B=3% C=5% D=7%
Growth Rate of Relative Weight (%)
Probiotics treatment
Table 2. Tilapia survival rate
Treatment Mean (%)
A (Pellets without probiotic) 97,78a
B (Pellets with 3% probiotics) 97,78a
C (Pellets with 5% probiotics) 97,78a
D (Pellets with 7% probiotics) 98,89a
Description: The average value followed by the same letter do not differ demonstrated
Survival rate is the number of fish that lived during the culture period and the number of stock fish. The value could be inversely related to mortality. Survival rate is influenced by several factors, including age, quality of water, food and disease pests. It is also supported by water quality conditions well within the normal range for fish growth.
Tilapia fish is known as well adapted fish either to a new environment or to the water temperature or other water qualities.
3.3. Feed Conversion Ratio
The value of feed conversion ratio is an overview of the level of efficiency of feed given. The smaller the feed conversion ratio, the more efficient of the feed was given in supporting the growth of fish (Mudjiman, 2000). Feed conversion ratio used to determine the poor quality of feed given to fish growth. The low feed conversion ratio means higher feed efficiency, and conversely higher feed conversion ratio, the lower the efficiency.
Tilapia fed with commerciall pellet without probiotics (A) shows the highest feed conversion ratio compare to the feed conversion ratio of fish fed with probiotics supplement (B, C and D) Table 3).
Table 3. Feed Conversion Ratio (FCR)
Treatment Mean
A (Pellets without probiotic) 2,57a
B (Pellets with 3% probiotics) 2,40b
C (Pellets with 5% probiotics) 2,42b
D (Pellets with 7% probiotics) 2,39b
Description: The average values followed by the same letter do not differ demonstrated by Duncan multiple range test on the significant level of 5%.
Analysis and Duncan test range of variations to the fish feed conversion ratio on feed type used exhibited that there were significant differences between treatment A (feed without probiotic) with other feeds fed probiotics, feed B(with the addition of probiotic feed3%), C(5%), D(7%). Feed conversion ratio varied in a range of 2.39 to 2.42 which gave a mean that in order to raise 1 kg weight of fish required 2.39 to 2.42 kg of feed.
General, the highest fish feed conversion ratio is up to grade 4 (Bardach et al., 1972).
The addition of probiotics to the fish feed conversion ratio has a value lower than that
without probiotics. This suggested that the feed used was preferred to stimulate the appetite of fish; as a result fish eats more food. Feed with probiotics had a distinctive aroma that was different from that of without probiotics. The aroma of feed containing probiotics stimulates the appetite. Probiotics are living microorganisms that can suppress populations of pathogenic microorganisms in the host animal. Probiotics can alter the balance of microflora in the digestive tract, so that feed becomes easier digested by the fish.
3.4. Water Quality
Water quality affects fish culture growth directly or indirectly. Measurement of water quality parameters was carried out to determine the state of the waters of captivity.
Several water quality parameters were measured including temperature, dissolved oxygen (DO), the degree of acidity (pH), ammonia (NH3). The results of water quality measurements during the culture period were shown on Table 4. Treatments of probiotic pellets caused the value of the quality of water entering to environment were better than that of pellets without probiotics treatment. The culture of tilapia using pellets with probiotics was more effective in reducing the rate of deterioration of water quality.
Table 4. The Values of Water Quality on Tilapia Culture
Water Quality Treatments
A B C D